The invention relates to a condenser for an air-conditioning system. In particular the invention relates to a condenser for an air-conditioning system of a motor vehicle. The condenser of the invention comprises lateral header tubes and a finned tube block. The finned tube block contains a section serving as a collector and comprises flat tubes and corrugated fins.
In a known condenser of the type disclosed in FR-A 2776 759, the collector is integrated as a reservoir into the finned tube block. In a first embodiment, a section of flat tubes which are connected in parallel and which correspond to the other flat tubes, serves as the collector. In another embodiment, the collector provided is only a single large-volume tube which projects beyond the contour of the condenser on at least one side. In further embodiments, flat tubes connected in parallel as well as an outer tube are provided. The outer tube is parallel to and has a larger cross section than the flat tubes. In this known construction, phase separation between liquid and vaporous refrigerant takes place in the section serving as a collector or reservoir. During transverse accelerations of the vehicle, for example, during cornering, the liquid level changes. These changes in liquid level may lead to an uneven cooling process or even to breakdowns in the cooling process, particularly when refrigerant has already been lost after a lengthy operating period. In a reservoir or collector of small cross-section flat tubes connected in parallel, the loss of refrigerant during lengthy operational periods is practically unavoidable. Even in the case of relatively low refrigerant losses, the losses lead to the displacement of supercooling to a relatively great extent, thereby impairing the cooling capacity of the air conditioning system. This displacement of supercooling may go so far that supercooling is no longer achieved at all within the condenser.
An object of the present invention is to provide an improved condenser, especially for use in automotive air-conditioning units.
A further object of the invention is to integrate a collector into the finned tube block of a condenser, in such a way that transverse accelerations have no effect on the cooling capacity and that refrigerant losses do not have too great an effect on condenser function.
In accomplishing the objects of the invention, there has been provided, according to one aspect of the invention, a condenser for an air-conditioning system comprising: a) a pair of headers; b) a finned tube block comprised of a plurality of flat tubes extending between the headers, wherein the tube block includes a plurality of first flat tubes having a first tube cross-section; and c) a collector integrated into the finned tube block, the collector comprising a plurality of second flat tubes having a second tube cross-section, wherein the second tube cross-section is a multiple of at least twice as large as the first tube cross-section, and wherein the second tubes are connected to the headers to provide serial flow through the second tubes.
Further objects, features and advantages of the invention will become apparent from the detailed description of preferred embodiments that follows, when considered together with the accompanying drawings.